An struct copy constructor that can cope with an AA?

[Steven Schveighoffer]

On 3/9/20 9:23 AM, mark wrote:
> I have this struct:
> 
> struct Deb {
>      string name;
>      ...
>      Unit[string] tags; // set of tags
> 
>      Deb copy() const {
>          Deb deb;
>          ...
>          foreach (key, value; tags) // XXX
>              deb.tags[key] = value;
>          return deb;
>      }
> 
>      void clear() {
>          name = "";
>          ...
>          tags.clear;
>      }
> 
> ....
> }
> 
> I am populating an AA with these structs:
> 
> Deb[string] debForName;
> 
> I'm using this approach (pseudo-code):
> 
> Deb deb;
> foreach (datum; data) {
>      populateDeb(datum, deb);
>      debForName[deb.name] = deb.copy; // YYY
>      deb.clear;
> }
> 
> (1) XXX Is there a nicer way to copy an AA?

aa.dup. However, this isn't going to work in a const member function 
(though technically there shouldn't be anything wrong with it).

> (2) YYY Is there a nicer way to copy a struct? Use a copy constructor or 
> implement a dup or idup?

I would name it dup instead of copy for consistency with D. A copy 
constructor is pretty heavy for a struct to do a complete duplication of 
the AA. You should have to opt-in to that.

-Steve